Anxiety at its finest.

So on the 14th of July I had intercourse using a condom. Never in the occasion did he finish. My last period was from July 1-5... I feel as if I'm late despite the fact these past few months I've been rather irregular. I've had random cramps and sharp pains in my abdomen area along with back pain and very mild nausea. Cervix is medium and firm, maybe a bit open? Should I be worried?